I contracted for a lot of companys in my time, and still do however now I tend to have people to look after contracts for me, one thing about hiring a contracter vs a employee, it will cost you more I would think in many cases, as the contracter is a professional, and self employed vs an employee.
Its also nice to get a 100% commitment from an employee and a contract saying they wont work for anyone else.
Then again there are some skillsets you may have to seek at time that only a contracter can deliver.